Treatment method of waste oil or waste edible oil

Abstract

Glycerin is effectively produced from a waste oil by a method comprising adding a strongly alkaline reducing water obtained by electrolyzing water containing sodium chloride to a waste oil selected from the group consisting of a waste edible oil, a fossil fuel waste oil and a mixture thereof, and extracting natural glycerin or synthetic glycerin by chemical reaction. Further, reusable edible oil is produced from a waste edible oil by a method comprising electrolyzing an aqueous solution having an electrolyte in an electrolytic cell, mixing a strongly alkaline reducing water generated at a cathode side of the electrolytic cell with a waste edible oil under ordinary temperature condition, and conducting oil/water separation, thereby purifying the waste edible oil to an extent such that it can be edible.

What is claimed is:  
     
       1. A treatment method of a waste oil, which comprises adding a strongly alkaline reducing water obtained by electrolyzing water containing sodium chloride to a waste oil selected from the group consisting of a waste edible oil, a fossil fuel waste oil and a mixture thereof, and extracting natural glycerin or synthetic glycerin by chemical reaction. 
     
     
       2. A treatment method as claimed in  claim 1 , wherein said water containing sodium chloride is water prepared by adding sodium chloride to fresh water, or sea water. 
     
     
       3. A treatment method as claimed in  claim 1 , wherein said strongly alkaline reducing water has at least pH of 11 to 12.5 and oxidation reduction potential (ORP) of −0.5 to −1.2 V. 
     
     
       4. A treatment method of a waste edible oil, which comprises electrolyzing an aqueous solution having an electrolyte in an electrolytic cell, mixing a strongly alkaline reducing water generated at a cathode side of the electrolytic cell with a waste edible oil under room temperature condition, and conducting oil/water separation, thereby purifying the waste edible oil to an extent such that it can be edible. 
     
     
       5. A treatment method as claimed in  claim 4 , which further comprises a step of recovering the treated oil by conducting water washing, dehydration and heat filtration after the oil/water separation. 
     
     
       6. A treatment method as claimed in  claim 5 , wherein said heat filtration is conducted using active clay, and deodorization is conducted by heating the treated oil and frying ginger slices in the heated oil. 
     
     
       7. A treatment method as claimed in  claim 4  or  5 , wherein calcium hydroxide is added to water after the oil/water separation to flocculate and precipitate the same as a calcium soap, and the water containing the precipitated calcium soap is mixed with a strongly acidic water, thereby obtaining the calcium soap and water capable of being discharged to sewerage. 
     
     
       8. A treatment method as claimed in  claim 4  or  5 , wherein said strongly alkaline reducing water has at least pH of 11 to 12.5 and oxidation reduction potential of −0.5 to −1.2 V. 
     
     
       9. A treatment method as claimed in  claim 4 , which is conducted by a system comprising a reservoir tank for waste edible oil and a reaction tank, each having an ultraviolet irradiation means arranged therein, and a system comprising a reservoir tank for waste edible oil having an ultraviolet irradiation means arranged therein, and a reaction tank having an ultraviolet irradiation means and a divalent iron ion supplying means arranged therein. 
     
     
       10. A treatment method as claimed in  claim 4 , wherein said oil/water separation comprises a method of mixing a strongly acidic water with an emulsion, or a method of mixing a hydrochloric acid-acidic water having pH adjusted to around 2.5 in place of a strongly acidic water containing free chlorine. 
     
     
       11. A treatment method as claimed in  claim 4 , wherein said electrolyte is at least one member selected from the group consisting of sodium chloride, sodium sulfate, sodium carbonate, potassium carbonate and calcium hydroxide. 
     
     
       12. A treatment method as claimed in  claim 4 , which is conducted by a system comprising an electrolytic cell, a reaction tank and an oil/water separation means. 
     
     
       13. A treatment method as claimed in  claim 4 , which further comprises ultraviolet irradiation or a combination of ultraviolet irradiation and addition of divalent iron ion to increase removal ability of peroxide.